1. Field of the Invention
The present invention relates to a DVD-RAM (Digital Video Disk-Random Access Memory) system, and in particular, to a method of processing the data of a defect sector referring to a defect list having physical defect information on a disk.
2. Description of the Related Art
In general, a disk has defect areas unavailable for recording data due to physical causes in a DVD-RAM system. Such defect areas are empty of data and their smallest unit is a data sector. A sector in a defect area is called a defect sector, and the information of the defect sector is generally stored in a lead-in area of a DVD-RAM disk.
FIG. 1 illustrates a data format for a general DVD-RAM disk, with a physical sector address preceding data to be error-corrected.
Since the information of a defect sector in the lead-in area is stored in an additional defect information memory, it is determined whether a physical sector address for each sector data indicates a defect sector referring to a defect list having the information of defect sector data in the defect information memory when the physical sector address shown in FIG. 1 is read during a playback of the DVD-RAM disk in the DVD-RAM system. If the physical sector address does not indicate a defect sector, the data following the physical sector address is stored in an error correction memory and subjected to error correction.
FIG. 2 is a block diagram of a signal processing portion 236 in the general DVD-RAM system to which the present invention is applied. Referring to FIG. 2, a memory 224 serves as an error correction memory and stores data in 16 data sector units. A microcomputer interface 226 interfaces data transmitted between components of the signal processing portion 236. A microcomputer 228 controls the entire operation of the signal processing portion 236 as well as that of the DVD-RAM system.
When reproducing a disk 200, a disk motor 204 starts to rotate at a constant linear velocity, and an optical pickup 202 including a head converts disk information to an analog high frequency signal. The analog high frequency signal is converted to a pulse wave signal and a data stream EFM is applied to a 32-bit shift register 206. The lower 16 bits of 32 bits output from the 32-bit shift register 206 are provided to a 16-to-8 demodulator 208. The 16-to-8 demodulator 208 converts the received 16-bit data to 8-bit data as one symbol because data was 8-to-16 modulated during recording.
A physical sector address detector 230 detects a physical sector address from the data received from the 16-to-8 demodulator 208. A physical sector address error corrector 234 corrects errors of the physical address received from the physical sector address detector 230. A data address detector/error corrector 232 detects a data address from the data received from the 16-to-8 demodulator 208 and corrects errors of the data address. A sync detector 210 detects various sync patterns like a frame sync signal being a standard signal for controlling the rotation of the disk 200, a sector sync signal for differentiating sectors, and an error correction sync signal for reading the data of a corresponding error correction block by finding out an error correction time point, and generates sync signals.
A descrambler 214 descrambles scrambled data recorded on the DVD to return the scrambled data to the state prior to scrambling. An error detector 216 detects errors from the data received from the descrambler 214. A deinterleaver 218 deinterleaves data interleaved in frame units to return the data to its original arranged state by controlling a write/read address of the memory 224. An ATAPI (AT Attachment Packet Interface) interface 222 interfaces data between the signal processing portion 236 and a computer. AN ATAPI buffer memory 238 temporarily buffers the data interfaced between the computer and the signal processing portion 236. A memory controller 220 stores data read from the disk 200 in the memory 224 in 16 sector units. An error corrector 212 corrects errors of a predetermined block having data read from the disk. A defect information memory 240 stores a defect list having information of defect sectors read from the lead-in area of the disk 200.
As shown in FIG. 2, the defect information memory is additionally provided in the prior art to store the defect sector information, thereby requiring an additional memory access means for controlling the defect information memory and increasing the number of memories.